手术前后三维动脉瘤模型的血液动力学模拟对比

本研究目的在于从临床患者的医学影像出发,在手术前后分别对三维动脉瘤模型进行了定常模拟,观察动脉瘤模型内的流场形态以及各血液动力学参数的变化并进行讨论。由于三维的数值模拟比二维的跟接近实际,而且更加直观形象,所以研究结果对于分析动脉瘤的破裂机理具有重要的临床应用价值。     

耕作的数值模型及其应用

种子发芽与出苗主要受土壤水分与温度的影响。在研究非均质土壤起伏不平的地表与大气间水分能量交换过程的数值分析方法的基础上,发展了耕作对土壤水分与温度影响的基于有限元分析方法的数值模型。作为应用研究,讨论了不同的耕作方式如镇压,少耕与沟种垄作对土壤水分、温度的影响,并介绍了模型用于陕北的沟种设计。本项研究为农业生态学提供了一种基于模型－模拟－优化的定量分析方法。     

犬囊状动脉瘤模型的制作

本文报道用“静脉囊镶嵌技术·制成犬的囊状动脉瘤模型。18个模型(6个单侧型,6个分叉型,6个末梢型)造型后2周经IA DSA检查。本模型在分型、血流动力学改变方面与人类囊状脑动脉瘤类似。不同类型的动脉瘤模型既有相同的血流动力学特征,又有各自的特点,这与动脉瘤与载瘤动脉的角度有关。我们认为该模型可应用于研究动脉瘤的血流动力学与血管内栓塞治疗。     

单株树下辐射分布的数值模型

以数值求解的方法建立单株树下的辐射分布模型。模型给出不同纬度、不同坡向、不同树形几何参数、不同树下的平面位置和不同时刻的辐射强度。由此编制了标准的Ｃ 和ＦＯＲ－ＴＲＡＮ 数值函数Ｉ＝ ｆ（ψ，α，Ｓ，Ａ，Ｈｂ，Ｈｃ，Ｒｏ，Ｘ，Ｙ，ｔ）。以新疆和田地区的核桃树下所测得的辐射数据进行拟合运算的结果说明，模型能较好的描述单株树下的实际辐射分布。最后，对树下的平均辐射的全年变化的分析表明，对树冠形状近于锥体的单株树，当树高和冠幅为定值时，增加冠高（减少枝下裸干高）反而能提高树下平均辐射     

NO在实验性大鼠颈动脉瘤发展中的作用

目的建立一种新的颈动脉动脉瘤模型,观察iNOS在实验性动脉瘤组织局部的表达情况和选择性iNOS抑制剂氨基胍对动脉瘤增大和对血清NO水平的影响。方法50只SD大鼠随机分为3组,应用弹性蛋白酶灌注颈总动脉建立颈动脉梭形动脉瘤模型。A组给予氨基胍干预;B组给予生理盐水;C组为阴性对照。测量颈总动脉直径和血清硝酸盐含量。应用HE、免疫组化和原位杂交评价动脉瘤的病理特征和iNOS的局部表达特点。结果选择性iNOS抑制剂可以明显抑制动脉瘤增大的程度和血清硝酸盐水平。诱导的动脉瘤病理特征和外形与人动脉瘤组织相似,主要表现为动脉瘤壁明显增厚,内弹力膜和弹性膜全部消失,平滑肌细胞层变薄和消失。中膜和外膜管壁大量的炎症细胞浸润,氨基胍明显抑制iNOS的表达。结论应用弹性蛋白酶灌注颈动脉可以在大鼠诱导出梭形动脉瘤。动脉瘤的增大与局部升高的NO有关。     

二维细胞运动模型的数值模拟

研究了一个二维细胞运动模型,该模型是个动边界问题．我们运用运动网格的有限元算法对此模型进行了数值模拟,数值结果表明,细胞最终收敛到固定形状,并且以固定速度向前运动．     

颅内动脉瘤栓塞术的临床分析

目的：用动脉瘤栓塞体积比评价颅内动脉瘤栓基术的治疗效果,观察颅内动脉瘤栓塞术治疗颅内动脉瘤的影响因素及颅内动脉瘤栓塞术的术后情况。方法：选取112例行血管内栓塞治疗的患者为研究对象,按术后动脉瘤栓塞体积比分成VER〉25％和VER〈25％两组,观察不同的栓塞材料（电解可脱弹簧圈、水解可脱弹簧圈）和术中血管的痉挛程度（轻、中、重）对栓塞程度的影响;术后随访106例病人,按动脉瘤栓塞体积比分成VER〉25％和VER〈25％两组,统计两组患者的再出血率和复发率,用动脉瘤栓塞体积比评价栓塞术的预后效果。结果：动脉瘤栓塞体积比VER〉25％和VER〈25％两组间进行比较,不同血管痉挛情况下和使用不同的栓塞材料在两组间均存在显著差异（P〈O．05）,具有统计学意义;术后随访半年,比较VER〉25％和VER〈25％两组的再出血率也有显著差异（P〈O．05）,具有统计学意义。结论：动脉瘤栓塞体积比在评价颅内动脉瘤栓塞术中有重要意义,血管痉挛情况、栓塞材料是影响颅内动脉瘤栓塞术栓塞疗效的主要影响因素;术后随访证实动脉瘤栓塞体积比对评价动脉瘤栓塞术的预后有一定的作用。     

显微手术夹闭颅内动脉瘤手术疗效分析

目的：探讨显微手术夹闭颅内动脉瘤手术的疗效。方法：回顾性分析自2005年10月至2010年10月期间开颅行夹闭颅内动脉瘤手术的39例患者的临床资料。结果：除有1例死亡外,其中29例恢复良好,能生活自理,7例伴有轻度残疾,需人照顾,2例重残,需要卧床。结论：夹闭颅内动脉瘤手术获得了较好的疗效,我们发现避开血管痉挛发生的高峰期即可达到较好的疗效,即在3日内或14日后实行手术较为适宜。     

人──板系统最佳蹬伸动作的控制模型及数值分析

本文基于Hanavan模型和人体测量学参数,以人体各环节间的相对运动作为控制量,建立了人-板系统中起跳蹬伸动作的数学模型,给出了模型的数值计算方法,在此基础上给出了实现最佳蹬伸用力过程的计算实验途径与运动技术诊断方法。     

颅内动脉瘤栓塞术的临床分析*

摘要目的：用动脉瘤栓塞体积比评价颅内动脉瘤栓塞术的治疗效果,观察颅内动脉瘤栓塞术治疗颅内动脉瘤的影响因素及颅内 动脉瘤栓塞术的术后情况。方法：选取112例行血管内栓塞治疗的患者为研究对象,按术后动脉瘤栓塞体积比分成VER≥ 25％和 VER＜25％两组,观察不同的栓塞材料（电解可脱弹簧圈、水解可脱弹簧圈）和术中血管的痉挛程度（轻、中、重）对栓塞程度的影 响;术后随访106 例病人,按动脉瘤栓塞体积比分成VER≥ 25%和VER＜25%两组,统计两组患者的再出血率和复发率,用动脉 瘤栓塞体积比评价栓塞术的预后效果。结果：动脉瘤栓塞体积比VER≥ 25%和VER＜25%两组间进行比较,不同血管痉挛情况下 和使用不同的栓塞材料在两组间均存在显著差异(P<0.05),具有统计学意义;术后随访半年,比较VER≥ 25%和VER＜25%两组 的再出血率也有显著差异(P<0.05),具有统计学意义。结论：动脉瘤栓塞体积比在评价颅内动脉瘤栓塞术中有重要意义,血管痉挛 情况、栓塞材料是影响颅内动脉瘤栓塞术栓塞疗效的主要影响因素;术后随访证实动脉瘤栓塞体积比对评价动脉瘤栓塞术的预 后有一定的作用。     

稳恒流下腹主动脉旁瘤超声多普勒血流信号的仿真分析

腹主动脉旁瘤超声多普勒血流信号的仿真研究,可以为采用超声多普勒技术检测腹主动脉旁瘤的形成、生长过程和估计动脉旁瘤瘤体大小提供指导。先通过有限元数值计算方法得到稳恒流下腹主动脉旁瘤区域内的血液流场分布,然后采用余弦叠加的合成方法仿真出相应的超声多普勒血流信号,最后对仿真信号进行频谱分析,计算其平均频率,并研究它与腹主动脉旁瘤瘤体大小的关系。结果表明：当动脉旁瘤较小时,平均频率的幅度变化较小;当动脉旁瘤较大时,平均频率的幅度变化较大。因此,采用平均频率的幅度变化可以在一定程度上估计动脉旁瘤的瘤体大小。     

腹主动脉瘤生长过程的蠕变力学模型

基于增强对腹主动脉瘤生长过程的理解、为腹主动脉瘤临床手术提供参考的目的,本文根据腹主动脉瘤的生长物理机制,提出了以蠕变力学为基础模拟腹主动脉瘤生长过程的模型.建立了腹主动脉瘤简化模型,利用有限元方法进行模拟计算.结果显示蠕变模型能够有效模拟腹主动脉瘤生长过程中的形态变化.参数优化模型模拟结果符合临床统计数据所示的腹主动脉瘤生长过程.本文还讨论了腹主动脉材料力学参数对模型的影响.     

腔内修复术治疗腹主动脉瘤的临床疗效分析

目的:评价腔内修复术(EVAR)治疗腹主动脉瘤(AAA)的临床疗效及安全性。方法:选择2008年12月至2013年12月收治的29例AAA患者,给予EVAR治疗,观察其围术期的疗效及血管破裂死亡、伤口愈合情况、截瘫、腔内隔绝术后并发症的发生情况和随访期疗效及血管破裂死亡、截瘫及内漏的发生情况。结果:29例手术均成功,1例术后3天出现右髂动脉支架内血栓、消化道出血及肝肾功能衰竭,行持续性血液净化好转出院。2例术区切口愈合延迟,9例术后发热,无在院死亡及截瘫病患。随访期间,1例术后30天死亡,死于肝肾功能衰竭;1例3个月出现肾功能不全;1例双下肢乏力,无截瘫发生。存活的28例患者复查增强CT见支架位置、形态良好,无移位及内漏发生。结论:EVAR具有成功率高、创伤小、恢复快等特点,且并发症少,治疗AAA安全有效。     

大戟科植物分类的数值分析

根据大戟科216个分类性状的分布,采用欧氏距离系数一类平均法对Webster(1994)广义大戟科49个族或亚族进行聚类分析。结果表明,现行的大戟科分类系统中,大多数族和亚族水平的分类基本合理,而Galearieae族的系统位置和五月茶族Antidesmeae等亚族的划分出现较大矛盾。该系统中未包含的方鼎木属Archileptopus,应与叶下珠族的Pseudolachnostylidillae亚族接近。     

Kinetics of Regional Blood-Brain Barrier Glucose Transport and Cerebral Blood Flow Determined with the Carotid Injection Technique in Conscious Rats

Anesthetics, particularly barbiturates, have depressive effects on cerebral blood flow and metabolism and likely have similar effects on blood-brain barrier (BBB) transport. In previous studies utilizing the carotid injection technique, it was necessary to anesthetize the animals prior to performing the experiment. The carotid injection technique was modified by catheter implantation in the external carotid artery at the bifurcation of the common carotid artery. The technique was used to determine cerebral blood flow, the Km, Vmax, and KD of glucose transport in hippocampus, caudate, cortex, and thalamus-hypothalamus in conscious rats. Blood flow increased two to three times from that seen in the anesthetized rat. The Km in the four regions ranged between 6.5 and 9.2 mM, the Vmax ranged between 1.15 and 2.07 mumol/min/g, and the KD ranged between 0.015 and 0.035 ml/min/g. The Km and KD in the conscious rat did not differ from the values seen in the barbiturate anesthetized rat. The Vmax, on the other hand, increased two- to three-fold from that seen in the anesthetized rat and was nearly proportional to the increase in blood flow seen in the conscious rat. The development of the external carotid catheter technique now allows for determination of BBB substrate transport in conscious animals.     

Extracellular-Purine Metabolism in Blood Vessels (Part I). Extracellular-Purine Level in Blood of Patients with Abdominal Aortic Aneurysm

Adenosine and adenosine derivatives are the main regulators of purinoceptors (P1 and P2) mediated hemostasis and blood pressure. Since impaired hemostasis and high blood pressure lead to atherosclerosis and to the development of aneurysm, in this study we tested and compared the concentration of extracellular purines (e-purines) in the blood in of patients having abdominal aortic aneurysm with that from healthy volunteers. Whereas adenine nucleosides and nucleotides level in human blood plasma was analysed using reverse phase high performance liquid chromatography (HPLC), cholesterol concentration was estimated by an enzymatic assay. We did not find any correlation between e-purines concentration and the age of healthy volunteers. Furthermore, the sum level of e-purines (ATP, ADP, AMP, adenosine, and inosine) in the control group did not exceed 70 μM, while it was nearly two-fold higher in the blood of patients having abdominal aortic aneurysm, (123 μM). In a special case of people with Leriche Syndrome, a disease characterized by deep atherosclerotic changes, the e-purines level had further increased. Additionally, we also report typical atherosclerotic changes in the aorta using histological assays as well as total cholesterol rise. The significant rise in cholesterol concentration in the blood of the patients with abdominal aortas aneurysm, compared with the control groups, was not unique since 23% of the healthy people also exceeded the normal level of cholesterol. Therefore, our results strongly indicate that the estimation of e-purines concentration in the blood may serve as another indicator of atherosclerosis and warrant further consideration as a futuristic diagnostic tool.     

Numerical Analysis of Blood Flow through COVID-19 Infected Arteries

Computational Fluid Dynamics has become relevant in the study of hemodynamics, where clinical results are challenging to obtain. This paper discusses a 2-Dimensional transient blood flow analysis through an arterial bifurcation for patients infected with the Coronavirus. The geometry considered is an arterial bifurcation with main stem diameter 3 mm and two outlets. The left outlet (smaller) has a diameter of 1.5 mm and the right outlet (larger), 2 mm. The length of the main stem, left branch and right branch are fixed at 35 mm, 20 mm and 25 mm respectively. Viscosity change that occurs in the blood leads to different parametrical changes in blood flow. The blood flow towards the smaller branch is significantly affected by the changed blood viscosity. Extended regions of high pressure and increased velocity towards the larger outlet are obtained. The Time Averaged Wall Shear Stress (TAWSS) for the corona affected artery is found to be 10.4114 Pa at a 90° angle of bifurcation as compared to 2.45002 Pa of the normal artery. For varying angles of bifurcation, an angle of 75° was found to have a maximum Time Averaged Wall Shear Stress of 2.46076 Pa and 10.42542 Pa for normal and corona affected artery, respectively.     

高血压患者颈动脉粥样硬化与血脂、血压和血尿酸水平的相关性分析

目的:探讨高血压患者颈动脉粥样硬化(CAS)与血脂、血压以及血尿酸水平的相关性。方法:选择2017年2月至2018年8月在我院就诊的高血压患者117例作为研究组,另选择同期在我院进行体检的健康志愿者50例作为对照组。采用彩色多普勒超声诊断仪测定所有受试者的颈动脉内中膜厚度(IMT),并根据研究组患者的颈动脉IMT将其分为斑块组(IMT≥1.3 mm,33例)、IMT增厚组(1.0 mm≤IMT1.3 mm,49例)和IMT正常组(IMT1.0 mm,35例)。比较研究组与对照组受试者IMT,同时分别比较研究组与对照组受试者以及不同IMT高血压患者平均收缩压(SBP)、平均舒张压(DBP)、血清总胆固醇(TC)、甘油三酯(TG)、低密度脂蛋白胆固醇(LDL-C)、高密度脂蛋白胆固醇(HDL-C)以及尿酸水平,并采用Pearson相关性分析法分析高血压患者IMT与各指标的相关性。结果:与对照组比较,研究组IMT、SBP、DBP、TC、TG、LDL-C、血尿酸水平升高,HDL-C水平降低,差异均有统计学意义(P0.05)。斑块组患者SBP、DBP、TC、TG、LDL-C、血尿酸水平高于IMT增厚组和IMT正常组,HDL-C水平低于IMT增厚组和IMT正常组,差异均有统计学意义(P0.05);IMT增厚组患者SBP、DBP、TC、TG、LDL-C、血尿酸水平高于IMT正常组,HDL-C水平低于IMT正常组,差异均有统计学意义(P0.05)。Pearson相关性分析显示,高血压患者的IMT与SBP、DBP、TC、TG、LDL-C、血尿酸均呈正相关,与HDL-C呈负相关(P0.05)。结论:高血压患者IMT与血脂、血压和血尿酸水平均有明显相关性,血压、血脂、血尿酸参与了高血压患者CAS的发生与发展。     

The Helsinki Rat Microsurgical Sidewall Aneurysm Model

Experimental saccular aneurysm models are necessary for testing novel surgical and endovascular treatment options and devices before they are introduced into clinical practice. Furthermore, experimental models are needed to elucidate the complex aneurysm biology leading to rupture of saccular aneurysms.Several different kinds of experimental models for saccular aneurysms have been established in different species. Many of them, however, require special skills, expensive equipment, or special environments, which limits their widespread use. A simple, robust, and inexpensive experimental model is needed as a standardized tool that can be used in a standardized manner in various institutions.The microsurgical rat abdominal aortic sidewall aneurysm model combines the possibility to study both novel endovascular treatment strategies and the molecular basis of aneurysm biology in a standardized and inexpensive manner. Standardized grafts by means of shape, size, and geometry are harvested from a donor rat''s descending thoracic aorta and then transplanted to a syngenic recipient rat. The aneurysms are sutured end-to-side with continuous or interrupted 9-0 nylon sutures to the infrarenal abdominal aorta.We present step-by-step procedural instructions, information on necessary equipment, and discuss important anatomical and surgical details for successful microsurgical creation of an abdominal aortic sidewall aneurysm in the rat.